com.willetinc.hadoop.mapreduce.dynamodb.AttributeValueIOUtils.java Source code

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Here is the source code for com.willetinc.hadoop.mapreduce.dynamodb.AttributeValueIOUtils.java

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/**
 * Copyright 2012 Willet Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.willetinc.hadoop.mapreduce.dynamodb;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.apache.commons.codec.binary.Base64;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.WritableUtils;

import com.amazonaws.services.dynamodb.model.AttributeValue;

public class AttributeValueIOUtils {

    public static AttributeValue read(Types type, DataInput in) throws IOException {
        AttributeValue value = new AttributeValue();
        switch (type) {
        case STRING:
            value.withS(Text.readString(in));
            break;
        case NUMBER:
            value.withN(Text.readString(in));
            break;
        case BINARY:
            byte[] bytes = WritableUtils.readCompressedByteArray(in);
            ByteBuffer buf = ByteBuffer.wrap(bytes);
            value.withB(buf);
        case STRING_SET:
        case NUMBER_SET:
        case BINARY_SET: {
            // handle sets
            int size = in.readInt();
            List<AttributeValue> values = new ArrayList<AttributeValue>(size);
            for (int i = 0; i < size; i++) {
                switch (type) {
                case STRING_SET:
                    values.add(read(Types.STRING, in));
                    break;
                case NUMBER_SET:
                    values.add(read(Types.NUMBER, in));
                    break;
                case BINARY_SET:
                    values.add(read(Types.BINARY, in));
                    break;
                default:
                    throw new IOException("Nested sets of sets are not permitted");
                }
            }
            break;
        }
        }

        return value;
    }

    public static void write(Types type, AttributeValue value, DataOutput out) throws IOException {
        switch (type) {
        case STRING:
            Text.writeString(out, value.getS());
            break;
        case NUMBER:
            Text.writeString(out, value.getN());
            break;
        case BINARY: {
            WritableUtils.writeCompressedByteArray(out, value.getB().array());
            break;
        }
        case STRING_SET: {
            List<String> values = value.getSS();
            out.writeInt(values.size());
            for (String s : values) {
                Text.writeString(out, s);
            }
            break;
        }
        case NUMBER_SET: {
            List<String> values = value.getNS();
            out.writeInt(values.size());
            for (String s : values) {
                Text.writeString(out, s);
            }
            break;
        }
        case BINARY_SET: {
            List<ByteBuffer> values = value.getBS();
            out.writeInt(values.size());
            for (ByteBuffer buf : values) {
                WritableUtils.writeCompressedByteArray(out, buf.array());
            }
        }
        }
    }

    public static Collection<AttributeValue> readCollection(Types type, DataInput in) throws IOException {
        int size = in.readInt();
        List<AttributeValue> list = new ArrayList<AttributeValue>(size);
        for (int i = 0; i < size; i++) {
            list.add(read(type, in));
        }

        return list;
    }

    public static void writeCollection(Types type, Collection<AttributeValue> values, DataOutput out)
            throws IOException {
        int size = values.size();
        out.writeInt(size);
        for (AttributeValue value : values) {
            write(type, value, out);
        }
    }

    /**
     * <p>
     * Creates a string representation of the specified AttributeValue.
     * </p>
     * 
     * <p>
     * Supported AttributeValue types are Number, String, and Binary. Throws an
     * IllegalArgumentException if any other types are specified.
     * </p>
     * 
     * @param type
     *            AttributeValue type
     * @param value
     *            value to serialize.
     * @return String representation of value.
     */
    public static String toString(Types type, AttributeValue value) {
        if (null == value)
            return null;

        switch (type) {
        case STRING:
            return value.getS();
        case NUMBER:
            return value.getN();
        case BINARY:
            ByteBuffer buf = value.getB();
            return Base64.encodeBase64String(buf.array());

        default:
            throw new IllegalArgumentException("Only String, Number and Binary types are supported");
        }
    }

    /**
     * <p>
     * Parses the specified string and returns and AttributeValue.
     * </p>
     * 
     * <p>
     * Supported AttributeValue types are Number, String, and Binary. Throws an
     * IllegalArgumentException if any other types are specified.
     * </p>
     * 
     * @param type
     *            AttributeValue type
     * @param value
     *            String generated by the AttributeValueIOUtils.toString()
     *            method.
     * @return Deserialized AttributeValue.
     */
    public static AttributeValue valueOf(Types type, String value) {
        if (null == value)
            return null;

        switch (type) {
        case STRING:
            return new AttributeValue().withS(value);
        case NUMBER:
            return new AttributeValue().withN(value);
        case BINARY:
            byte[] bytes = Base64.decodeBase64(value);
            return new AttributeValue().withB(ByteBuffer.wrap(bytes));
        default:
            throw new IllegalArgumentException("Only String, Number and Binary types are supported");
        }
    }

}